Abstract: An apparatus which is disposed in an exhaust system of a diesel engine for treating particulate emissions contained in exhaust gas is disclosed. The apparatus comprises a splittable casing body including an inlet-side casing portion and an outlet-side casing portion, an inlet pipe secured to the inlet-side casing portion, an outlet pipe secured to the outlet-side casing portion, a partition plate detachably retained between the inlet- and outlet-side casing portions such as to divide the inside of the casing body into two compartments, and at least one filter assembly detachably mounted in an opening provided in the partition plate. The filter assembly is defined by a honeycomb-type ceramic filter which is accommodated in a metallic casing and surrounding by a cushioning material, and which has a catalyst carried on its internal passage wall. The catalyst enables a lowering in the combustion temperature of the particulate emissions.